This invention relates to a rotary internal combustion engine. Rotary engines have a number of advantages over standard reciprocating engines. One advantage is the much smaller number of moving parts needed. In addition, with reciprocating engines a considerable amount of energy is wasted in stopping parts and then causing them to move in the opposite direction. Much vibration, heat and wear results from this.
According to a first aspect of the present invention there is provided a rotary internal combustion engine comprising two rotors mounted within a housing for rotation about respective central axes which are substantially parallel to each other, each rotor having a series of radially projecting lobes which are equally spaced circumferentially and which intermesh with the lobes of the other rotor to form successive combustion chambers as the rotors rotate, said housing being provided with a sealing plate on each axial side of the rotors, the sealing plates being in sealing engagement over an active area which axially seals each combustion chamber formed by the rotating intermeshing rotors throughout a full combustion cycle.
Preferably four intermeshing rotors are provided in two pairs, the central axes of the rotors being provided on the corners of a square, each pair of rotors providing said successive combustion chambers which are axially sealed by said sealing plates. In a preferred embodiment each sealing plate is generally diamond shaped, the short axis of which is generally parallel to imaginary lines extending between the central axes of each pair of rotors.
Another preferred feature is that the axially inward facing surface of one of the sealing plates is provided with a groove arrangement to facilitate escape of exhaust gasses. Ideally the groove arrangement comprises a central exhaust through bore equidistant from the central axes of all four rotors, with four angled grooves extending from the central bore towards the edges of the sealing plate. In some arrangements both sealing plates are provided with one of said groove arrangements.
A further preferred feature is that the peripheral edge of each sealing plate tapers outwardly in a direction axially away from the rotors. Also at least one of the sealing plates provides orifices for fuel delivery to the combustion chamber and at least one of the sealing plates provides ignition means.
According to a second aspect of the present invention there is provided a drive arrangement incorporating a rotary internal combustion engine comprising two rotors mounted within a housing for rotation about respective central axes which are substantially parallel to each other, each rotor having a series of radially projecting lobes which are equally spaced circumferentially and which intermesh with the lobes of the other rotor to form successive, sealed combustion chambers as the rotors rotate, the rotors each having a shaft which extends through the housing to engage a drive system for driving a driven member in rotation relative to the housing about a drive axis.
In a preferred arrangement the drive arrangement is mounted on an axle having the central drive axis, the housing is fixed relative to the axle and the drive member is driven in rotation about the axle and also the driven member is a wheel with a bearing disposed between the wheel and the axle.
Preferably the rotors are mounted in bearings in the housing and also the rotor shafts extending through the housing are attached to drive cogs which mesh with a cooperating drive ring mounted on the wheel.
It is a preferred feature that the axle incorporates an axial through bore for exhaust products, fuel delivery and electricity delivery for ignition means where necessary and a central tube for exhaust products is provided in the axial through bore and extends through the housing. In addition the housing is provided with communication means for the fuel delivery, electricity delivery for ignition means where necessary and for exhaust products.
Conveniently four intermeshing rotors are provided in two pairs, the central axes of the rotors being provided on the corners of a square, each pair of rotors providing said successive, sealed combustion chambers.
According to a third aspect of the present invention there is provided a rotary internal combustion engine comprising two rotors mounted within a housing for rotation about respective central axes which are substantially parallel to each other, each rotor having a series of radially projecting lobes which are equally spaced circumferentially and which intermesh with the lobes of the other rotor to form successive sealed combustion chambers, each lobe having a tip and a leading face in the direction of rotation, each tip and each leading face being provided with an axially extending strip seal arrangement each comprising an axially extending through slot formed in the rotor and a pair of axial seal elements retained in the slot, the axial seal segments each having a portion projecting beyond the rotor and being of the same axial length as the rotor.
With a preferred arrangement each axial face of each rotor is formed with a peripheral groove which communicates with the through slots and which houses an edge seal which sealingly links the axial seal segments. In some arrangements the edge seal for one axial face of each rotor is formed in lengths, each length being integrally formed with one of the axial seal segments of at least one pair of axial seal segments. Conveniently the edge seal for one axial face of each rotor is formed integrally with one of the axial seal segments of all of the pairs of axial seal segments, the edge seal for the other axial face being formed integrally with the other axial seal segments of all the pairs of axial seal segments.
Preferably the axial seal segments at the tips are urged radially outwardly and the axial seal segments in the leading faces are urged outwardly in the direction of rotor rotation. In one embodiment the axial seal segments at each rotor tip are urged radially outwardly by weights received in respective bores which communicate with the axial slot so that the weights can contact the inner ends of the axial seal segments and each rotor tip has two of said bores which are angled and which extend from opposite respective axial faces of the rotor, cross inside the lobe and extend to the axial slot. With some arrangements each pair of axial seal segments in each leading face is urged by spring means.
In certain preferred embodiments the edge seals are urged axially outwards by spring means. Conveniently said spring means comprises a number of through bores extending between the grooves on opposite axial faces, each through bore accommodating a spring disposed between two pistons to urge them into engagement with the oppositely disposed edge seals.
It is a preferred feature that each axial through slot has a first section opening to a second section inwardly thereof, the second section being wider than the first section such that the axial slot retains the axial seal segments and also that each pair of axial seal segments are mirror images of each other and have abutting planar surfaces.